He ran three-and-a-half miles to the YMCA and then ran all the way back every other day in his home of Forest, Va. On weekends he ran some more.

His mother thought he was crazy. People in the neighborhood wondered why he ran so much. Jennings was heading into his senior year of high school and he had a thought that he could play football in college. But chubby and out of shape, as he tells it, few noticed him, so Jennings started running.

Six years later, Jennings is still running and blocking and catching after a winding road to the NFL. On Sunday against the Oakland Raiders, Jennings, who backs up running back Maurice Jones-Drew for the Jaguars, had his first 100-yard game, rushing for a team-high 109 yards, including a 74-yard touchdown run.

In a sense, he followed in the footsteps of two brothers who played in the NFL. But really Jennings' path was completely his own.

"Earning respect and trust from my teammates and the coaches is very rewarding," Jennings said. "You train every single day. You prepare your mind like you're a starting back. That's how every single player should be in their position. ... Whether it might be one play that you're called upon or whether or not it's 15 plays. The number doesn't matter."

Before many people knew his name, Jennings went to two high schools and repeated his junior year. He split his time at two colleges as well.

Offers to play big-time college football began arriving for Jennings in the summer before his senior year of high school, after the running began. Jennings went to football camps and collecting offers. The first came from Pittsburgh, and that was the school he chose.

Jennings played at Pittsburgh as a true freshman, becoming only the fourth true freshman running back to start for the program. But after one season with the Panthers, Jennings left. His father's diabetes had gotten worse, he needed a leg amputated, and Jennings wanted to be close to home.

His family told him to stay at Pittsburgh and chase his dream, but Jennings wouldn't hear it. He transferred to Liberty, a small school in Lynchburg, Va., and spent the next three years there.

"I got hazed a lot for transferring by media," Jennings said. "'This guy's throwing away his shot at playing in the National Football League. Going to an unknown school.' They were 1-10 at the time."

Jennings rushed for a Big South record 3,633 yards and 42 touchdowns at Liberty.

But it was still Liberty and that meant getting noticed would be that much harder. He went to the NFL combine, but ran a 4.67-second 40-yard dash, which didn't help.

Though projected to be one of the top 10 running backs taken in the 2009 draft, Jennings fell to the seventh round, and the Jaguars took him 250th overall.

Once in Jacksonville, he still had more to prove.

"I think you start earning trust and gaining the confidence of your teammates and the coaching staff when you do your job," Jaguars coach Jack Del Rio said. "Just do your job and then your ability has a chance to kind of take over, but first make sure you're where you're supposed to be. If you have blitz pick-up, be there. If you have to run a route in a certain depth, get to the certain depth.

"So all the fine points and the details of playing the position, I think he's really gotten where he's executing with confidence and become very dependable for us."

Jennings has scored a touchdown in the Jaguars' past three games. His increased role is starting to give the Jaguars the kind of double-threat backfield they had when Fred Taylor was their starter and Jones-Drew was his backup.

Also for the past few weeks, Jennings' locker had been roped off from the rest of his teammates by the kind of partition found in bank lines or airports. Safety Don Carey's locker is to his right and fullback Montell Owens to his left. They said it was because Jennings was so messy, but Jennings insisted the opposite was true, later saying quietly, that he was willing to play along with the joke.

It came down briefly, but after Sunday's game it went back up and even Del Rio meandered over to take a bemused look.

It was an unconventional sight in the locker room, perfectly fitting of a player whose entire football career has been unconventional.